Noise from BLDC Motor with Instaspin

There is no noise when not setting gMotorVars.Flag_enableSys to 1 and gMotorVars.Flag_Run_Identify to 1.When it starts to initializing the position 0 the noise occurs. it will not become louder or lower when it spins(0 RPM or a larger RPM) or stop at a fixed position. Its volume is same.

This noise volume will become louder when I rotate the motor to generate a small angle error by hand.

There are something different.
1. In my prototype system, the magnetic encoder is much closer to the motor. the distance is about 1 cm.
In my EVM system, the distance is about 5 cm.

2. In my prototype system, many 0402 resistors and capacitors are used. Is it possible there is no enough power for the motor?

3. In my prototype system, there is no 1-ohm resistor between AGND and board GND.

Hello, Chris,

PWM frequency is
#define USER_PWM_FREQ_kHz (45.0)

motor parameters are
#define USER_MOTOR_TYPE MOTOR_Type_Pm
#define USER_MOTOR_NUM_POLE_PAIRS (7)
#define USER_MOTOR_Rr (NULL)
#define USER_MOTOR_Rs (8.284804344) // Identified phase to neutral resistance in a Y equivalent circuit (Ohms, float)
#define USER_MOTOR_Ls_d (0.003350858) // For PM, Identified average stator inductance (Henry, float)
#define USER_MOTOR_Ls_q (0.003350858) // For PM, Identified average stator inductance (Henry, float)
#define USER_MOTOR_RATED_FLUX (0.124141) // Identified TOTAL flux linkage between the rotor and the stator (V/Hz)
#define USER_MOTOR_MAGNETIZING_CURRENT (NULL)
#define USER_MOTOR_RES_EST_CURRENT (1.0)
#define USER_MOTOR_IND_EST_CURRENT (-1.0)
#define USER_MOTOR_MAX_CURRENT (3.0)
#define USER_MOTOR_FLUX_EST_FREQ_Hz (20.0)
#define USER_MOTOR_ENCODER_LINES (4096)
#define USER_MOTOR_MAX_SPEED_KRPM (2.0)
#define USER_SYSTEM_INERTIA (0.0141748)
#define USER_SYSTEM_FRICTION (0.279680)

I found some capacitors(220pf, C19/C20/C21/C22 and C25/C26/C27/C28) are not soldered on the EVM board. Before I removed these parts from my prototype board, the project 2a can not identify the motor parameters correctly. After removing them, the identification process is good, the identified parameters are like with ones from the EVM boards. The pars are so important?

Also now the noise gets down too. There is no louder noise when rotating the motor to a small angle error.
But one problem occurs.
When rotating the motor left to a small angle error, I can sense there is a hard torque to hold the position 0. At the same time the power supply(24V DC for motor) current can rise up to 1000 ma.
When rotating the motor right, I can not sense a hard torque to hold the postion 0. the holding torque is not enough. At the same time the power supply current rises up to about 400 ma.

There is no such a problem in the EVM board.

thank you

These capacitors on the TI DRV8312EVM board are not soldered.

Most of above problems have been solved. It is my mistake.

(1) I washed the pcb board because I used the flux and all components are placed intensively.
(2) The drv8312 chip has some problem. When it outputs high level of the pwm signal, Channel A can not be pulled up to power voltage 24V(only about 10V and always shaking).

Now there is some noise. But it is not loud.

Thank you, Chris.

Hi Fei Yan,

Does only Channel A show a problem? Can you check the other two channels to see if they still behave properly.

I would inspect Channal A for partial shorts/opens/soldering defects. I would also try and verify you setup on another PCB.